How about solving small, but important problems? There are countless examples of people using tech to improve people's lives in a way that matters.

Just look at the winners of this year's Microsoft Imagine Cup: http://www.imaginecup.com/blogs/imagine_cup_finals/default.a... - Apptenders, team from Croatia, built a physical therapy app for Kinect that helps children with cerebral palsy, quote: "KiDnect is a Kinect-based solution for on-premise and remote physical therapy for children, especially those born with Cerebral Palsy. This software has the ability to monitor a child’s exercises to ensure they are being completed correctly, and then provides statistical analysis to the therapist."

I would argue that the problems of the world are solved by solving small important problems, one at a time. And there's a world of opportunity for every startup to do just that!